Singh's sister Dalbir Kaur, who is fighting for the release of Singh who is languishing in Pakistan jail for the past over 20 years, said they cannot express in words the pain they have suffered.
Hours after reports emerged on Tuesday that Pakistan was to free Sarabjit, Presidential spokesman Faratullah Babar had said it was not Sarabjit but another Indian prisoner Surjeet Singh, who has been jailed for three decades.
"The pain we have suffered I cannot express. I don't think this should have happened. After the cruel joke they have played, isn't it necessary for Pakistan to improve its image to release Sarabjit immediately," Kaur told reporters.
She said she is appealing to Pakistan government to release Sarabjit for the sake of humanity.
49-year-old Sarabjit was convicted and sentenced to death for alleged involvement in a string of bomb attacks that killed 14 people in Punjab in 1990.
